1. Field of the Invention
The invention relates in general to special process for manufacturing multi-layered adhesive tapes, wherein the multi-layered adhesive tapes are easily portable adhesive tapes capable of saving space for convenient carrying.
2. Description of the Related Art
Conventional adhesive tapes usually are designed with circular inner core, such as paper core, plastic core or similar core. Recent developments have led to the flat adhesive tapes 12. Hollow orthogonal flat plastic tubes are made by ejection molding or hollow square flat paper tubes are designed by bending card board, as reference number 10 shows in FIG. 1. Adhesive tape is then unwounded out from jumbo roll and slitted into a desired tape. The tubes 10 are individually winded up into the flat adhesive tapes 12. However, such a manufacturing method requires a long working time and higher cost. Moreover, this kind of flat adhesive tape cannot provide necessary special physical properties, for example, super-transparence and coherence, due to the occurrence of trapped bubbles when the adhesive tapes are individually winded up.
If the conventional adhesive tapes are compressed directly to become the flat adhesive tapes, the inner tubes are distorted and the outside surface of the adhesive tapes is deformed by applied stress. Moreover, a strong rebound force remains in the distorted material, for example, the tube and tape. The more distortion occurs in a short time, the more rebound force there is. Besides, due to intrinsic properties such as visco-elasticity and memory of the substrate and adhesive layer of the adhesive tape structure, after the compression stress is removed the relaxation of the structure accompanied by a rebound force drive the adhesive tape to a stable state. The rebound force drives the adhesive tape to regain the tape's original shape. The strength of the rebound force depends on the deformation degree on the each position of the adhesive tape. The strength of the rebound force further depends on the thickness of the substrate, mechanical strength of the substrate, physical properties of the adhesive layer, adhesion, total length, central length of the symmetric plane (internal diameter before performing the compression step), and the winding up tension of the adhesive tape.